python data_error ai_generated true

AssertionError: assert {'a': 1, 'b': 2, ...} == {'a': 1, 'b': 3, ...} Omitting 15 identical items, use -vv to show Differing items: {'b': 2} != {'b': 3}

ID: python/pytest-assertion-dict-diff-truncated

Also available as: JSON · Markdown · 中文
80%Fix Rate
82%Confidence
0Evidence
2024-10-19First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
7.x active — — —
8.x active — — —

Root Cause

pytest truncates large dict/list diffs by default; the actual divergence is hidden among omitted items, making the failure hard to diagnose in CI logs.

generic

中文

pytest 默认截断大型字典/列表差异；实际分歧隐藏在省略项中，使 CI 日志中的失败难以诊断。

Workarounds

  1. 90% success 
    Raise verbosity:
pytest -vv tests/test_config.py::test_merge
# or set in config
# [tool.pytest.ini_options]
# addopts = "-vv"
  2. 85% success 
    Or compute a minimal diff explicitly:
from deepdiff import DeepDiff
diff = DeepDiff(expected, actual, ignore_order=True)
assert not diff, diff

Dead Ends

Common approaches that don't work:

  1. 65% fail

    Output is captured and interleaved unpredictably; hard to diff visually in CI.

  2. 50% fail

    Works but noisy and slow; you lose pytest's structured diff.